Conventional gas turbine engines include a turbine assembly that has a plurality of turbine blades attached about a circumference of a turbine rotor. Each of the turbine blades is spaced a distance apart from adjacent turbine blades to accommodate movement and expansion during operation. Each blade includes a root that attaches to the rotor, a platform, and an airfoil that extends radially outwardly from the platform.
A seal and damper assembly is installed between adjacent blades. The seal and damper assembly prevents hot gases flowing over the platform from leaking between adjacent turbine blades as components below the platform are generally not designed to operate for extended durations at the elevated temperatures of the hot gases. The seal and damper assembly also dissipates potentially damaging vibrations.
The seal and damper assembly is typically positioned in a cavity between adjacent turbine blades on an inner surface of the platforms. Typically, the seal and damper assembly is disposed against a radially outboard inner surface of the platform of the turbine blade and is retained in place by a small nub formed on the inner surface of the platform. The cavity also typically includes shelves to radially retain ends of the seal and damper assembly.
While the shelf and nub configurations serve to retain the seal and damper assembly, during assembly and engine operation the seal and damper assembly is not always fully constrained from movement with the cavity. In certain situations the seal and damper can disengage from the shelf and fall into the disk, which requires the rotor to be taken apart and rebuilt. Also, during engine operation the nub does not prevent tangential movement of the seal and damper within the cavity. Some seal and damper assemblies have shown large distortions from nominal shape, which is caused by high platform temperatures and lack of seal and damper retention in the cavity.
Accordingly, it is desirable to provide a seal and damper which is easily installed and which is restricted from moving within a pocket formed between adjacent high pressure turbine blade platforms.